In the realm of advanced thermal management and electrical conductivity solutions, the Graphite Sheet stands out as a material of exceptional performance and versatility. Engineered from highly pure natural or synthetic graphite, these sheets are processed through a sophisticated exfoliation and compression technique. This results in a thin, flexible, yet robust planar material that aligns graphite's naturally superior properties—notably its high thermal conductivity and excellent electrical conductivity—in the in-plane direction.
Unlike traditional metal heat spreaders, graphite sheets are remarkably lightweight and can be easily die-cut into complex shapes to fit specific applications. Their primary function is to efficiently dissipate heat away from hot spots in electronic devices, such as CPUs, GPUs, LEDs, and smartphone batteries, ensuring optimal performance and longevity. The material's flexibility allows it to conform to uneven surfaces, creating an efficient thermal pathway without adding significant mechanical stress.
Our graphite sheets are manufactured to the highest industry standards, ensuring consistent quality and performance for demanding applications. Below is a detailed breakdown of their core features and technical specifications.
The performance of a graphite sheet varies based on its thickness and density. We offer a range of products to suit different thermal and spatial requirements.
| Thickness (µm) | Thermal Conductivity (In-Plane, W/m·K) | Thermal Resistance (°C·cm²/W) | Density (g/cm³) | Tensile Strength (MPa) | Typical Applications |
|---|---|---|---|---|---|
| 17 | 1500 - 1900 | 0.1 - 0.15 | 1.1 - 1.3 | > 6 | Ultra-thin smartphones, compact wearable devices |
| 25 | 1600 - 1950 | 0.15 - 0.25 | 1.2 - 1.4 | > 8 | Tablets, laptops, high-density LED lighting |
| 50 | 1700 - 2000 | 0.3 - 0.5 | 1.3 - 1.5 | > 12 | Telecom equipment, power supplies, automotive displays |
| 100 | 1800 - 2100 | 0.6 - 0.9 | 1.4 - 1.7 | > 15 | Battery pack thermal management, server modules |
| Property | Value / Description | Test Standard / Condition |
|---|---|---|
| In-Plane Electrical Conductivity | 1.0 x 105 to 2.5 x 105 S/m | ASTM D257 |
| Through-Plane Thermal Conductivity | 5 - 20 W/m·K | ASTM E1461 (Laser Flash) |
| Shore Hardness | 10 - 30 (Shore A Scale) | ASTM D2240 |
| Compressibility | 10% - 30% under 50 psi | Custom fixture test |
| Long-Term Use in Air | Up to 250°C - 300°C (Oxidation effects increase above this) | Continuous operational rating |
Q: How does a graphite sheet work for thermal management?
A: A graphite sheet functions as a superb planar heat spreader. Heat generated from a concentrated source (like a chip) is rapidly conducted along the sheet's large lateral plane due to its high in-plane thermal conductivity. This action effectively "spreads" the heat over a much larger surface area. Once spread, the heat can be more efficiently transferred to the surrounding air, a heat sink, or the device chassis via convection or conduction, thereby lowering the peak temperature of the hot component. It does not act as a heat sink itself but as a highly efficient conduit to move heat away from critical areas.
Q: What is the main difference between natural and synthetic graphite sheets?
A: The core difference lies in the raw material source and some resulting properties. Natural graphite sheets are derived from purified mined graphite flakes. They often offer a slightly higher initial thermal conductivity and can be more cost-effective for standard applications. Synthetic graphite sheets are produced by graphitizing polymer films (like polyimide) at extreme temperatures. They typically provide exceptional purity, more consistent uniformity in structure and performance, and can achieve higher thermal conductivity values at the upper end of the scale. Synthetic variants are often preferred for high-reliability and premium-performance electronics.
Q: Can graphite sheets be used for EMI shielding?
A: While graphite sheets are excellent electrical conductors in-plane, they are not typically the first choice for dedicated EMI (Electromagnetic Interference) shielding in the traditional sense. Their primary role is thermal management. However, their conductivity can provide some level of electromagnetic compatibility (EMC) benefit by creating a grounded conductive plane, which can help mitigate certain types of interference. For robust EMI shielding, specially designed conductive foils, fabrics, or coatings with higher through-plane conductivity are generally more effective.
Q: How do I install or apply a graphite sheet?
A: Installation is straightforward but requires care. The graphite sheet is usually die-cut to the precise shape of the component or area. One or both sides may come with a pressure-sensitive adhesive (PSA) for easy mounting. Ensure the surface is clean, dry, and free of debris. Peel the liner and carefully apply the sheet, smoothing it out to avoid air bubbles or wrinkles. For non-adhesive versions, a thin layer of thermal grease or a thermal adhesive tape on both sides might be necessary to ensure good thermal contact. Avoid excessive bending or folding during handling to prevent cracking.
Q: Are graphite sheets fragile? How should they be handled?
A: Graphite sheets are flexible but can be susceptible to tearing if mishandled, especially the ultra-thin grades (e.g., 17µm). They should be handled by the edges whenever possible. Avoid sharp tools or fingernails directly contacting the surface. When die-cutting or storing, keep them flat and away from sharp objects. While they can conform to curves, they should not be creased or folded back on themselves sharply. For automated assembly, use vacuum pickup tools or gentle handling fixtures.
Q: What are the limitations of using a graphite sheet?
A: Key limitations include: Anisotropy: Their thermal conductivity is highly directional (excellent in-plane, poor through-plane). This must be considered in the thermal design. Oxidation: At sustained high temperatures in air (above ~300-350°C), graphite can oxidize, degrading performance. For high-temp applications in air, protective coatings or alternative materials may be needed. Mechanical Strength: While tensile strength is good for its weight, it is not a structural component and can be punctured. Electrical Conductivity: Its conductive nature means it must be carefully isolated from electrical shorts on PCBs.
Q: Can I replace thermal pads or thermal grease with a graphite sheet?
A: A graphite sheet often serves a different, complementary purpose. Thermal grease is a TIM (Thermal Interface Material) designed to fill microscopic air gaps between two solid surfaces (e.g., CPU and heat sink). A graphite sheet is a heat spreader. In many applications, they are used together: thermal grease ensures optimal contact between the chip and the graphite sheet, and the sheet then spreads the heat. It can sometimes replace thick, low-conductivity thermal pads when the goal is both gap filling and lateral heat spreading, offering superior thermal performance in a thinner profile.
Q: How do I select the right thickness for my application?
A: Selection depends on thermal requirements and space constraints. Thinner sheets (17-25µm): Best for extremely space-constrained devices (smartphones, wearables) where minimal thickness is critical. They offer very low thermal resistance for their profile. Medium sheets (50µm): A versatile choice for balancing performance and handle-ability in laptops, LEDs, and general electronics. Thicker sheets (100µm+): Used for higher heat flux applications or where mechanical robustness is a secondary concern, such as in battery packs or between power modules and chassis. A thermal simulation is recommended for critical designs.
